Toyota Grand Highlander loss of power problems

Filed Oct 24, 2026 · Transmission · MD

Transmission Whining Noise Detected, Automatic Shifting Difficulties, Reduced Power & Acceleration Concerns. Dealer inspected and confirmed transmission failure. Required Dealer replacement under power train warranty. Defect known to exist in Toyota 6 speed Automatic U80A transmissions. Transmission is known to be defective and unreliable, potentially causing catostrophic injury to persons and property with use and operation.

Filed Oct 13, 2026 · Driver assistance, Electrical · IN

My Toyota Grand Highlander Hybrid Limited has 16000 miles. Yesterday, 5 vehicle alerts appeared simultaneously: Check Engine, AWD system, Drive-Start control system, Intelligent clearance Sonar, and Hybrid system. The vehicle has reduced power and check engine light is illuminated. I towed the vehicle to dealership. They found damage to inverter radiator causing a leak of coolant. Dealership mentioned that this could be because of flying debris hitting the vent. I am requesting a goodwill technical review and repair of the same. Referencing to the federal safety agency defect petition DP26006 where people have encountered similar issues with the grand highlanders from 2024-2026.

Filed Oct 6, 2026 · Transmission · OH

While driving in neighborhood at around 25 mph car started to sputter and lose power. Started flashing on display regarding ADAS which all disengaged then hybrid system failure message displayed. Stopped car, called dealership and asked if safe to drive. They said it was ok and set appointment for next morning, they contacted Toyota and confirmed it needed a new transmission. Gave me a rental and said car was do not drive. Said transmission backordered under warranty.

Filed Oct 3, 2026 · Fuel system · IL

Design flaw of front grille of vehicle causing major damage. Due to the large gaps in front grille, the vehicle is susceptible to rock damage to the coolant system. Under normal highway driving, coolant started to leak and immediate power loss put my wife at risk. She was unable to accelerate to maintain speed while on a busy highway. There are no immediate signs for damage since any small rock can pass through the grille and create multiple punctures. You don't know something is wrong until symptomatic and then your placed at risk and also others around you.

Filed Sep 4, 2026 · Transmission · TX

When ambient temperature are over ~90 the vehicle will lose power during acceleration. This happens typically in the speed range of ~20-35mph. The vehicle’s rpm will spike high but lose the ability to increase speed or shift gears. This occurs ~ 40-50% of the time when over 90 degrees. On several occasions we were forced to abandon merging onto the highway because the vehicle wasn’t safely able to accelerate to match the speed of vehicles on the highway. We reported this issue to our local Toyota dealer September 2025. After reviewing the vehicle they said nothing was wrong. We had them drive it longer and they agreed the vehicle had these issues. The dealership spoke with Toyota and they confirmed there was an issue for our vehicle and a lot of others and they had no fix for it. That was September 30, 2025; Toyota Brand Engagement Center Reference # 250923001413. There has been no communication from Toyota or our dealer since then. The safety issue with the vehicle is a major concern in operation of the vehicle and with the hot climate we live in, is putting our occupants and others on the road at risk and we feel Toyota needs to be held accountable for finding the issue(s) and correcting them.

Filed Aug 23, 2026 · Fuel system · NY

During driving on a highway at highway speed (not off-roading), A road debris or rock went through the front grille's hole and damaged the cooling system which leaked coolant and i experienced a loss of power and propulsion while driving on highway, as a result of this issue.

Filed Jul 16, 2026 · Engine, Fuel system · IL

I've had consistent issues with the vehicle accelerating and shifting. These include sluggish acceleration, loss of power and sputtering when we've come to a complete stop and starting to move again. We've almost been hit by other vehicles at least over 20 times because the vehicle has failed to accelerate when pulling into a roadway. The car hesitates during acceleration regardless of how much I push the gas. Once it starts to go, it feels as though the car can't shift from 1st to 2nd gear, The RPMs get extremely high while the car is going 25-40 mph and remain there for a few seconds up to ~20 seconds. I am fearful of getting t-boned when my car hesitates while turning at an intersection, going through an intersection or pulling out from a parking lot. I have been stuck in several intersections when traffic was coming toward me, but thankfully those cars had patience and avoided us. I've also found that this issue always happens when the hybrid battery shows that it only has a charge of 3 bars. It seems that the engine, transmission and hybrid battery don't know how to communicate when the battery charge gets that low. This has been happening since Dec 2023 when I bought the vehicle and the dealer has never been able to duplicate or find any error code, they are refusing to fix a known issue when many others are experiencing the same issue. There are Toyota Technical Service Bulletins (TSBs) out there regarding this problem but my dealer told me they won't do anything as it could label my vehicle a lemon. This is creating an unnecessary safety risk for me and my family.

Filed Jun 25, 2026 · Electrical, Engine · MO

While driving my 2024 Toyota Grand Highlander Hybrid AWD at highway speed with only 16,755 miles on the vehicle, multiple warning messages suddenly appeared, including warnings related to the engine, hybrid system, AWD system, and other vehicle functions. The vehicle instructed me to pull over immediately and significantly reduced power output, making it difficult to maintain highway speed and safely maneuver through traffic. I was able to reach the shoulder and had the vehicle towed to a Toyota dealership. The dealer diagnosed a punctured radiator caused by a rock or similar road debris that allegedly passed through the front grille and struck the radiator. The dealer confirmed that coolant loss from the puncture triggered the vehicle's protective reduced-power mode. This failure created a significant safety risk. A sudden loss of power while traveling at highway speed increases the risk of rear-end collisions and other accidents, particularly in heavy traffic where drivers may not expect a vehicle to rapidly decelerate. There were no warning lights, messages, leaks, drivability concerns, or other symptoms before the incident. All warnings appeared suddenly at the time of failure. Toyota has declined warranty coverage, classifying the damage as a road hazard. However, I believe this may indicate a design defect. I have identified numerous reports from other GH owners describing nearly identical failures involving rocks penetrating the radiator through the front grille, often at relatively low mileage. These reports suggest the radiator may be inadequately protected from ordinary roadway debris. My concern is not simply radiator damage, but that a small piece of road debris encountered during normal driving can disable a critical component and cause the vehicle to enter a severe reduced-power mode at highway speed. I request that the federal safety agency investigate whether the front grille and radiator protection design of the Grand Highlander creates an unreasonable safety risk

Filed May 26, 2026 · Engine, Fuel system · VA

Failed System: Fuel Injector Failure (?) at high speeds, under load (uphill), causing an immediate and life threatening loss of power. While traveling on the highway, going up mountainous areas, the vehicle loses power and shakes violently. During multiple repairs/visits, the dealerships state that it is the failure of fuel injectors. They are replaced, and it happens again with the same explanation. Safety: Three times my family has lost power at 70mph while traveling uphill surrounded by many cars. The last event ended in a a scary and close interaction with an 18 wheel truck that was unable to stop as we lost power. Dealer Confirmation: The dealer has confirmed, on two separate occasions, that the fuel injectors needed replaced. The vehicle has 3,000 miles on it. At 2,000 miles, damage was found to the fuel injectors. They were replaced and the car was placed back in my possession. At 3,000 miles, the incident occurred for the 3rd time and damage was again found with the fuel injectors. Inspection: Dealerships as well as Toyota's field technician have inspected/repaired the vehicle 2 times and is currently at a dealership for the 3rd time. Warning messages: After the incident occurs, multiple warning lights appear (check engine and hybrid system malfunction).

Filed Aug 20, 2025 · Acceleration, Engine · IL

I've had consistent issues with the vehicle accelerating and shifting. These include sluggish acceleration, loss of power, sputtering, and limp mode. We've almost been hit by other vehicles almost 10 times because the vehicle has failed to accelerate when pulling into a roadway. The vehicle will start to accelerate slowly, then stop, then 5-10 seconds later will surge forward will the engine revs very high and is delayed shifting into 2nd gear. I've told my Toyota dealership about this numerous times but they keep telling me that there's no issue but there clearly is being that many others are experiencing the same exact problems. There's never been a warning lamp or message when this happens. This is a huge safety issue and my family is extremely lucky that we haven't been involved in a serious accident.